Timing apparatus



Oct. 24, 1944. R, CANDOR 2,361,262

TIMING APPARATUS Filed May 24, 1945 5 Sheets-Sheet l Oct. 24, 1944. R CANDOR 2,361,262

TIMING APPARATUS Filed May 24, 1945 5 Sheets-Sheet 2 TIME 77/76 PILOT PILOT LIGHT 516N111. SIGNAL ua/n r42 BUZZER SL/ITCI/ su/rcfl OVEN Tl/YER LINE TERMINAL BLOCK NEUTRAL OVEN! F 1/4 829 I38 g5 Oct. 24, 1944. R. R. CANDOR TIMING APPARATUS Filed May 24, 1945 5 Sheets-Sheet 5 ah Q @w Oct. 24, 1944. R. R. CANDOR TIMING APPARATUS Filed May 24, 1943 5 Sheets-Sheet 4 Oct. 24, 1944. R. R. CANDOR 2,361,262

TIMING APPARATUS Filed May 24, 1943 5 Sheets-Sheet 5 Patented Oct. 24, 1944 TIMING APPARATUS Robert R. Candor, Oakwood, Ohio, assignor to General Motors Corporation, Dayton, Ohio, a.

corporation of Delaware Application May 24, 1943, Serial No. 488,139

Claims.

The present invention relates to timing apparatus, such as time switches, interval timers and the like.

One of the principal fields of utility for the invention is in that group of domestic or household time switches which are used on electric ranges or the like, and which are adapted to be set by the housewife to automatically control the starting and stopping of a cooking operation. My improved time switch preferably has one adjustment which is set corresponding to the time when the cooking operation is to stop, and another adjustment which is set corresponding to the number of hours or fraction of an hour required for the performance of the cooking operation.

To do this I provide separate discs for each adjustment, each being provided with an aperture or perforation which, when any portion of each are in registration uncover a colored background such as red or black, which contrasts with the color and/or appearance of the discs to indicate by its extent of exposure with reference to the clock dial the start, stop and duration of the cooking period. This colored background is illuminated by indirect lighting so that the cooking period will be indicated by an illuminated area in the portion of the clock dial corresponding to the time of the start, stop and duration of the cooking period. While this is the preferred relation of the adjustments, the invention is not necessarily limited thereto, but also includes other relations wherein the settings correspond to a definite hour for starting the cooking and a definite hour for stopping the cooking, or correspond to a definite hour for starting the cooking and an adjustable cooking time.

Another feature of the invention resides in the concentric grouping of these adjustments with respect to the clock dial of the electric switch. This simplifies the making of the adjustments because the two adjustments are thus directly related by such concentric grouping; also, because the setting of the stop cooking adjustment can then be made directly with reference to the hour and fractional hour markings on the clock dial. These clock dial markings are large and widely spaced, and the above adjustment can therefore be made more easily and more accurately than when small separate dials are used. The concentric grouping also results in a more compact structure, and in a decidedly better appearance, avoiding the impression of complicated manipulation.

The time responsive mechanism for controlling the electrical switch of the device comprises a stud or roller which is continuously moved at a predetermined rate through a closed path of travel by the clock mechanism of the time switch. For example, this roller is preferably continuously revolved in a circular path concurrently with the hour hand of the electric clock, whereby the roller completes one revolution through said path every twelve hours. Interposed in this path are two cams which, upon being encountered by the roller, cause the roller to be displaced in a direction axial of the circular path. Said cams are independently adjustable to any desired relative spacing in said path. One of the cams is adjusted by the aforementioned adjusting member which predetermines when the cooking operation is to stop, and the other cam is adjusted by the other adjusting member which predetermines the interval of the cooking operation. Such operating relation of adjustable cams and time driven roller affords a very simple, compact construction, and one which lends itself well to the concentric grouping of the adjusting members referred to above.

The above described displacement of the time driven roller, upon successive engagement thereof with the adjustable cams, efiects the tripping of the electric switch successively to different positions. This portion of the mechanism comprises a control shaft arranged to be spring-impelled in one direction of rotation, and movable in successive steps to different angular positions, each of which effects an opening or a closing of the electric switch. Said control shaft carries a plurality of angularly spaced stop shoulders which project outwardly from the shaft to progressively larger radii. These stop shoulders engage successively against a tripping lever which is arranged to respond to the axial displacement of the time driven roller. The tripping lever is successively withdrawn from engagement with one stop shoulder, and then the next stop shoulder etc., resulting in a step-by-step rotative movement of the control shaft, this movement causing the electric switch to be closed and opened in timed sequence as established by the setting of the aforementioned adjustable mem bers. At the completion of the automatic cycle, the switch is adapted to be restored to its normal closed position by a manual restoring operation performed through the medium of the tripping lever, so that the range is restored to its normal manual control.

Another feature of the device pertains to an interval timer which is driven by the electric clock of the time switch, and which can be set by the housewife to sound a buzzer upon the lapse of any desired time intervals, ranging say from three minutes to sixty minutes or longer. This interval timer is advantageous for indicating to the housewife the termination of a certain time period that she wishes to be reminded of in connection with a cooking or other culinary operation.

Other features, objects and advantages of the invention will hereinafter appear in the following detail description of one embodiment of my invention. In the accompanying drawings illustrating such embodiment:

Fig. 1 is a front elevational view of my improved electrical timing apparatus;

Fig. 2 is a circuit diagram of the device;

Fig. 3 is a vertical longitudinal sectional view through the mechanism, corresponding to a section taken approximately on the planes of the lines 3-3 of Figs. 1 and 4;

Fig. 4 is a horizontal sectional view taken approximately on the plane of the line 4-4 of Fig. 2;

Fig. 5 is a fragmentary vertical view taken approximately on the plane of the line 55 of Fig. 4;

Fig. 6 is a detail sectional view taken approximately on the plane of the line 8-6 of Fig, 3;

Fig. 7 is a detail sectional view taken approximately on the plane of the line 1--1 of Fig. 3;

Fig. 8 is a vertical sectional view through the buzzer and switch of the interval timer, corresponding to a view taken approximately on the plane of the line 8-8 of Fig. 4;

Fig. 9 is a detail elevational view of the movable switch element of the interval timer;

Fig. 10 is a transverse sectional view taken approximately on the plane of the line ll8 of Fig. 9;

Fig. 11 is a sectional view taken along the line H-Il of Fig.3;

Fig. 12 is a sectional view taken along the line l2l2 of Fig. 3;

Fig. 13 is a fragmentary sectional view taken 1 along the line l3l 3 of Fig. 1;

Fig. 14 is a fragmentary sectional view taken along the line 14- of Fig. 1;

Fig. 15 is a fragmentary sectional view taken along the line l-l5 of Fig. 1; and

Fig. 16 is a fragmentary sectional view showing additional indirect lighting for indicating the cooking period.

Referring to Fig, 1, the housing 2| which is preferably composed of a plastic or the like is of box-like form comprising a front wall and four side walls extending rearwardly therefrom, this housing or cover being secured to a base as will be presently described. The front wall of said housing has a large central opening therein surrounded by a dial ring 22 of the electric clock, this dial ring being provided with the usual hour and fractional hour markings 23, and the hour and minute hands 24 and 25 respectively. A resetting knob 26 extends forwardly from the front side of the cover glass 21, this knob being operative to reset the hands of the clock if the clock motor should stop by reason of current failure or any other cause. The cover glass 21 is held in place by the dial ring 22 and fits into the recess provided in the face of the housing 2|.

Concentric with the clock dial are two rotatable adjusting members 28 and 28 which are settable to different positions to predetermine the starting and stopping of the cooking operation. The adjustable member 28 is preferably in the form of a disk located beneath the dial ring 22. This adjusting member 28 is supported upon four idler gears 528 which ride upon four spacing wheels 628. The adjusting member 28 is rotated by a knob 28' bearing the legend off dial which is mounted at the outer end of the knob shaft I28 provided with a pinion 828 which meshes with the toothed edge of the adjusting member 28. The off dial knob 28 is rotated in order to rotate the adjusting member 28 to place the index arrow marked "off" to designate in cooperation with the clock dial the particular time at which it is desired to terminate the cooking operation or whatever operation is being controlled.

The other adjusting member 29 is likewise in the form of a disk mounted upon four idler gears 529 which mesh with the toothed edge of the adjusting member 29. The edges of the adjusting member 29 are further supported by four rotatable washers or wheels 828 beneath the idler gears 525. The idler gears 528 and 529 as well as the members 528 and 828 are all freely rotatable upon the stationary shafts 928 provided for their support. A knob 29' bearing the legend on" dial is provided upon the outer end of a rotatable shaft 129 which protrudes through the dial ring 22. The lower end of the shaft 529 is provided with a pinion 828 which meshes with the toothed edge of the adjusting member 28 in order that it may rotate the adjusting member 29 when the knob 28' is rotated.

The adjustment member 29 bears an on" index legend. This cooperates with a second series of hour and fractional hour markings 3| provided upon the adjusting member 28 as is best shown in Fig. 11. These markings designate the length of time that the cooking operation is to continue. After the adjusting member 28 is set to the time at which it is desired that the cooking operation should be completed, for example, about 5:30 o'clock, as illustrated in Fig. 1, the adjusting member 28 may be moved so that its legend on may be set to the fractional hour marking 3| which indicates the necessary length of the cooking time. For example, in Fig. 1 the length of the cooking time is illustrated as being three and one-half hours since the adjusting member is shown set with the on" legend indicating three and one-half hours. In addition, the on" legend also cooperates with the clock dial hour and fractional hour markings 23 to indicate the time at which the cooking operation will commence. For example, in Fig. 1, two oclock is indicated by the "on legend.

To make the indication of the cooking period clearly visible from a distance I provide a semicircular aperture or window 51 in the adjusting member 28. This aperture extends counterclockwise from th off" legend and its semicircular edge is provided with the hour and fractional hour markings 3|. Adjusting member 29 is likewise provided with a semi-circular aperture or window ill which, however, extends in a clockwise direction from the on legend. Thus the apertures or windows extend toward each other from the on" and off" legends. Instead of a single large aperture or window in the adjusting members 28 and 28 any suitable substitute, such as a multitude of perforations or slots may be used. The registering portion of the apertures or windows extends between the on and "off positions and reveals a background 530 which may be of some suitable contrasting color or appearance, such as red or black, or it may be a multi-colored background or a plain or diffused reflecting surface. This background may be provided upon a sheet member 830 supported by the upper frame plate 41.

Preferably this background may be indirectly lighted by the pilot light 42, and/or some other lights suitably placed. For example, three lights may be located laterally with respect to the background 630 and the adjusting members 28 and 29 as shown in Fig. 16, and substantially uniformly spaced around the clock dial to provide uniform indirect lighting of the'background 630. Each may be provided with a reflector to properly direct the light upon the background 630. The three lights may be connected in series with each other and in parallel with the pilot light 42 under control of the pilot light switch I46 as shown in Fig. 2. In fact the three lights may be used in the place of the pilot light 42, if desired. By this arrangement the red or black, or multicolored or reflecting background which is revealed provides an indication which is visible from a distance, designating the beginning and ending of the cooking operation as well as the length of cooking time. By providing indirect illumination this will be visible even in the dark, and can be understood because of its relation to the clock dial.

Spaced to one side of the clock dial is a control knob 33' which is secured to the upper end of an oscillatable control shaft 33 (Fig. 3). Projecting from said knob is a pointer portion 33" which is adapted to coact with the "set marking 34 and the off marking 35 to designate two of the four positions of the control knob 33". control shaft 33 and knob 33' are tubular, and a reciprocable plunger rod 38 extends downwardly therethrough, the upper end of this rod projecting above the knob or button 33 and being adapted to be depressed when the housewife desires to trip the control mechanism and restore the electric switch to its normal, closed circuit position, thereby placing the electrical heating element of the range back under manual control. The restoration of the electric switch to normal, closed circuit position results in the control knob 33 revolving downwardly to present its pointer portion 33" to a lower or normal position, below the off position 35.

Also formed at any desired point in the front wall of the housing is an opening into or through which extends the upper end of a pilot light 42. This pilot light is arranged to be illuminated so long as the control shaft 33 is either in its set position 34, its off position 35, or in its on position intermediate these two, thereby indicating to the housewife that the timing switch is functioning, or is still in control of the particular range circuit which leads from this timing switch. The pilot light is only extinguished when the control shaft 33 is restored to its normal,

closed circuit position, to which position said shaft moves when the plunger rod 38 is depressed, as described above. The indirect lighting may be similarly controlled.

Disposed to the other side of the clock dial is the interval timer knob 44. The periphery of this knob is marked with minute graduations 44, ranging say from zero to sixty. These marks are adapted to be brought into registration with an index pointer 45 on the casing when it is desired that the interval timer shall sound an audible signal upon the lapse of a selected time interval, as will be later described in detail.

Referring now to Figs. 3, 4, 5, etc., the working parts of the mechanism are supported in a frame structure comprising upper and lower frame plates 41 and 48 and an extension plate 49, the

The.

sembly is suitably secured to a lower base member 51 composed of insulating material. The left hand part of the frame plate 48 has an extending portion 48a which is dropped to a lower plane, and mounted on this extending portion is the electric motor 6! which drives the clock and other driven parts of the mechanism. In almost all instances, this electric motor will be synchronous alternating current motor of any preferred construction, such as are commonly employed in electric clocks and the like. It will of course be understood that if a frequency regulated alternating current is not available for operating such a motor, the latter might be substituted by conventional spring-driven clock mechanism, or by an accurately regulated electric motor of another type. Extending downwardly from reduction gearing within the base of the motor unit 6| is a pinion shaft 62 carrying pinion'teeth 63, which mesh with an idler gear 64 supported by a strap-like bracket 65. The idler gear meshes with teeth 66 formed on the lower end of a vertically disposed rotatable shaft 61, which has its lower end journaled in the bracket 65 and its upper end journaled in the upper frame plate 41. Gear teeth 68 formed in the upper portion of the shaft 61 are arranged to drive the interval timer, which will be later described.

latter extending from the left hand edge of the upper plate 41. The plates 41 and 48 are joined together in spaced relation by suitable screws and spacing posts 55 (Fig. 4), and the plate as- Th aforementioned teeth 66 in the lower portion of the shaft drive the large spur gear H which is disposed at the lower end of the clock assembly. Such gear is adapted to have a frictional clutch drive with the axial shaft or spindle 12 which carries the minute hand 25 at its upper end. The extremity of this minute hand shaft extends out through an opening in the cover glass 21 of the clock dial and has the resetting knob 26 secured thereto. A pinion I3 is fixedly staked to the minute hand shaft 12, and has a hub portion extending downwardly through the large gear H, the lower end of this hub portion having a. spring armed spider I4 fixedly secured thereto. The large gear II is capable of frictional rotation on the pinion hub,

between the body of the pinion and the spider 14, the operating relation being such that the gear "H normally transmits timed rotation to the minute hand shaft 12, but said minute hand shaft is capable of rotation relatively to said gear in the operation of setting the clock hands through manipulation of the resetting knob 26. The hour hand 24 of the clock is secured to the upper end of an hour hand sleeve 16 which surrounds the minute hand shaft 12. The appropriate speed reduction is transmitted from the minute hand shaft to the hour hand sleeve through laterally disposed reduction gearing illustrated in Figs. 4 and 5. This comprises a large spur gear 11 which is driven by the spur pinion 13 on the minute hand shaft. Extending upwardly from the gear 11 in fixed relation thereto is a relatively long spur pinion l8. Said gears 11 and 18 are mounted on a vertical shaft 19 which has its lower end supported in a bracket portion 48b extending from the lower frame plate 48, and which has its upper end supported in the upper frame plate 41. The relatively long pinion 18 transmits rotation to a spur gear 8| which is fixed to the lower end of the hour hand sleeve 16 and which transmits one complete rotation to the hour hand every twelve hours. Said long spur gear '18 also transmits this same identical rate of rotation to a time-driven roller which rotates through a circular path externally of the hour hand sleeve 16, as I shall presently describe.

Extending downward from the adjustable member 28 is a pointed cam 98 best shown in Figs. 3, 4, 5 and 11. This cam will assume different positions of adjustment about the axis of the minute hand shaft and the hour hand sleeve in accordance with the adjustment of the stop adjusting member 28. In similar fashion a pointed cam 99 projects downwardly from the on" or start adjusting member 29. This pointed cam 99 therefore assumes different angular positions about the minute hand shaft 12 and the hour hand sleeve 16 in accordance with the setting of the on adjustment member 29. The cam 98 is bent so that it will pass through the central aperture in the adjusting member 29 as well as the central aperture in the background sheet member 630 and extends around the bushing 98 which is threaded onto the upper end of the supportin sleeve 83 and is lodged against the shoulder provided thereon. The cam 99 rotates in the path of movement which is just outside the path of movement of the cam 93 and also extends through the central aperture in the background sheet member 630. By this arrangement the cams are independently adjustable. In the normal operation, first the short cam 99 and then the long cam 98 are engaged in that sequence by the aforementioned roller I I, which revolves continuously around the outer side of the supporting sleeve 83. Said roller is rotatably mounted on a stud I02 projecting radially outwardly from a time-driven shifter sleeve I03 which is mounted for rotation and reciprocation on the outside of the supporting sleeve 83. A gear I04 is rigidly secured to the lower end of the sleeve I03, this gear having the same diametral pitch as the gear 8| and also meshing with the relatively long gear 18 which drives gear 8|. Thus sleeve I03 and roller IOI rotate at the same speed as the hour hand 24, i. e. one complete revolution in twelve hours, the gear I04 remaining in continuous mesh with the relatively lon gear 18 during axial reciprocation of the sleeve I03 along the supporting sleeve 83. Downward reciprocation of the roller I0! and sleeve I03 occurs each time that the roller IOI encounters the cams 98 and 99. As clearly shown in Fig. 5, the two cams are of unequal length in a downward direction, the cooking hours cam 99 being relatively short and causing the sleeve I03 to move down a relatively short distance, whereas the stop cooking cam 99 is relatively longer, and causes the sleeve I03 to move down a greater distance.

An annular groove I06 is formed in the lower portion of the shifter sleeve I03, whereby the shifting movement of the sleeve is transmitted to a time controlled tripping lever I01 (see Fig. A laterally extending arm of said lever is formed with a rounded end portion I08 which engages in the annular groove I06, for transmitting reciprocal motion of the shifter sleeve to the lever. The lower end of the lever I01 is pivotally supported by the lower frame plate 09 in any suitable manner; in the exemplary arrangement shown the pivot mounting is established by extending the lever down through a slot in the plate, and by having a stud or protuberance III projecting from the lever and engaging the top of the plate, and a cotter-pin II2 passing through the lever and engaging the bottom of the plate. A spring bias is continuously exerted against the lever tending to swing it to the right (Fig. 5), such being effected by a wire sprin II having one end extending through a hole in the lever I01. The intermediate portion of the spring is given several turns around a stud H5 projecting downwardly from the top plate 1, and the other extremity of the spring is anchored against a lug II! also projecting downwardly from the plate 41. The upper extremity of the bell crank tripping lever I01 is arranged to oscillate back and forth in a long narrow guide slot H3 punched in the upper frame plate 41 (Fig. 5), this guide slot sustaining the lever against the lateral stresses exerted against the lever by the spring impelled control member to be now described.

This control member, designated I20 in its entirety, comprises the aforementioned control knob 33' and control shaft 33, together with the multiple stop plate H9 and switch actuating cam I, both mounted on the tubular shaft 33 to have rotative movement therewith. Referring to Fig. 4, the multiple stop plate H9 comprises three successive stop shoulders I22, I23 and I24 adapted to engage successively against the side surface of the tripping lever I01 as the control shaft 23 is angularly advanced, step by step, in a clockwise direction. The stop shoulder I23 projects outwardly to a larger radius than the stop shoulder I22, and the stop shoulder I 24 projects outwardly to a larger radius than the stop shoulder I23, whereby as the tripping lever I01 is retracted in steps, it will successively release the stop shoulders I22 and then I29, for producing a step by step advancing movement of the control shaft 33. When the index pointer 33" of the control knob 33' is in the set position 34, as shown in Fig. 1, the stop plate H9 occupies the position illustrated in Fig. 4, with its first stop shoulder l 22 abutting against the side of the tripping lever I01. The continuous, time-driven motion of the roller IOI brings it into engagement with the relatively short, cooking hours cam 99 for effecting the first tripping actuation of the lever I01,

the lever being oscillated to a limited extent just sufficient to free the stop shoulder I22. Immediately, the control shaft is oscillated in a clockwise direction under the impetus of a torsion spring, to be later described; this bringing the next stop shoulder I23 up against the side of the tripping lever I01. Following this, at the conclusion of the cooking interval, the longer cam 99 is encountered by the continuously moving roller IOI and a further retractive movement is thereby imparted to the tripping lever I01. This frees the second stop shoulder I23, which permits the control member to rotate through its next step of movement, bringing the third stop shoulder I24 up against the side of the tripping lever I01. Referring to Fig. 5, the stop surface on the side of the tripping lever I01 which is engaged by the successive stop shoulders I22-I 20 may be sloped or accurately machined, as indicated at I01 for insuring accurate tripping of the successive stop shoulders I22-424. The aforementioned torsion spring is indicated at I20, this spring being coiled around the lower portion of the control shaft with one end hooked to a shoulder on the switch actuating cam I2I and the other end hooked in an aperture in the lower frame plate 49, this spring tending constantly to rotate the control assembly in a clockwise direction, as viewed in Fig. 4.

The switch actuating cam plate "I comprises a shoe-like formation defining a flat cam spot HI and two cam lobes or projections HI" and I2 I located to each side of the flat spot. These cam surfaces engage successively against a strip I28 composed of fiber, vulcanite or other relatively stiff insulating material. One end of this strip is fixedly anchored by screws or rivets I29 (Fig. 4) and the other end is free to flex inwardly and outwardly under the action of the cam surfaces I2II2I"'. This flexing motion of the insulating strip is imparted to a pair of parallel movable contact springs I3I, I3I. Said contact springs have their fixed ends anchored under the screws or rivets I29, and carry contact buttons at their free ends which are adapted to engage with cooperating contact buttons on a pair of stationary contacts I32, I32. These stationary contacts are likewise anchored by screws or rivets I33. The movable and stationary pairs of switch contacts are assembled upon an insug lating panel structure built up of three strips of insulating material I34, I and I36, the screws or rivets I29, I33 passing through the two outer strips I35 and I36. As shown in Fig. 4, a horizontal, slot-like opening I31 is provided in the three insulating laminations, through which opening the switch operating cam I2I moves in imparting switch actuating motion in the insulating strip I28. To provide a mounting for the insulating base structure I34I36 of the switch,

the two frame plates 41 and 46 are formed with upwardly and downwardly extending end flanges 41c and 480 respectively (Fig. 3), and the base or panel structure of the switch is assembled up against these vertical flanges. Thereafter, hookshaped lugs or tabs 41d and 48d, extending from the flanges 41c and 480 respectively, are bent horizontally to hook over lugs I35 which project from the upper and lower edges of the insulating plate I35. Fig. 4 shows two of these hook-shaped lugs in dotted lines, and it will be noted that the lowermost lug 48d embraces the lower edge of the lug I35, so as to lock the panel structure against edgewise displacement from under the hook-shaped lugs. The insulating base 51 is formed with a terminal block portion 51a adjacent to the switch assembly, and mounted on a raised central portion of this block are two terminals I38, I38, and mounted on the outer lower portions of said block are two terminals I39, I39. As shown in Figs. 4 and 5, terminal clips I4I extend from the upper pair of switch contacts I3I, I32 to the terminals I38, I38, and terminal clips I42 extend from the lower pair of switch contacts I3I', I32 to the outer terminals I39, I39. The four stationary terminals extend downwardly through said mounting block into a cavity 51c formed in the underside of the insulating base 51, the electrical conductors being led into this cavity for connection with the lower ends of said terminals.

The pilot light 42 as well as the three lights 542 are responsive to the angular position of the control shaft 33, and, to this end, a cam I45 is mounted on said control shaft and arranged to control a switch I46 which is connected in circuit with the pilot light 42 and the three lights 542 for indirect lighting. The cam I45 is indicated largely in dotted lines in Fig. 4, and is of such configuration that it serves to hold the switch I46 closed for maintaining the pilot light and the indirect lighting illuminated during the entire time that the successive stop shoulders I22, I23, and I24 are engaging the tripping lever I01, the cam I45 only passing beyond the contact springs I 46 and permitting them to separate after the stop shoulder I24 has been tripped beyond the tripping lever I01, such flnal position of the control member leaving the main power switch I3I-I32 in closed position. As shown in Fig. 3, the pilot light switch contacts I46 have their lower ends suitably mounted on the insulating base 51, one of these switch elements being connected through a conducting strip I48 (Fig. 4) with a terminal of the lamp socket I5I into which the pilot light 42 screws. Referring to Fig. 3, the stop plate II9, main switch cam plate I2I and pilot switch cam plate I45 are all rigidly assembled in their proper angular relation on an assembly hub I53, which hub is thereafter adjustably secured to the tubular control shaft 33 by set screw I54.

Referring to the circuit diagram of Fig. 2, it will be seen that the automatic timer switch I3I.I32' is connected in series with a conventional manually actuated switch I55 which is provided for each heating element of the range. Thus, the energization of the heating element I56, located in the oven or any part of the range, requires that the automatic timer switch and the manual switch be both in their closed positions. However, when the automatic timer switch automatically stops the cooking operation it leaves the switch I3 II32 in open circuit position, the

stop shoulder I24 of the control member engaging at this time against the side of the trip lever I01. Accordingly, to place the heating element I56 back under the control of the manual switch I55, for manual starting and stopping of a cooking operation, it is necessary that the automatic swtich I3I--I32' be restored to closed circuit position. This is effected by the housewife pressing inwardly on the aforementioned plunger rod 38 that extends downwardly through the tubular control shaft 33. As shown in Figs. 3 and 6, the lower end of this rod extends out of the lower end of the tubular shaft or sleeve 33, and is operative to impart rocking movement to an arm I6I. This arm is an integral extension of r a rocker plate I62 which has pivotal mounting within a slot I53 punched in the lower frame plate 48. The plate I62 has a tongue portion which extends down through the slot and receives a transverse cotterpin I64 at a point below the frame plate 48, such mounting affording inexpensive pivotal support for the rocking plate. An arm I 61 extends forwardly from the other end of said plate, and is formed with a rounded extremity which engages within the annular groove I 06 formed in the time-driven shifter sleeve I03. As previously described, this shifter sleeve is normally urged upwardly toward its uppermost position by a spring II4 which acts through the tripping lever I01. The depressing of the plunger rod 38 acts through the arm I6I, rocker plate I62 and arm I61 to depress the shifter sleeve I03 downwardly to the lower limit of its movement, thereby swinging the tripping lever I01 through a maximum range of retractive movement, and thus releasing the last stop shoulder I24 of the stop plate II9. This permits the control shaft to rotate through a final clockwise step, for moving the cam lobe I2l out of engagement with the insulating plate I 23, enabling the switch contacts I3I, I3I to move to closed circuit position. The automatic timer is now reset to its normal closed circuit condition, so that further control of the heating element I56 is placed under the control of the manual switch I55, at least until it is desired to employ the timer for another automatic cycle. It will be noted that the resetting operation can be performed at any time by merely depressing the plunger rod 38, as for example to release either of the other stop shoulders I22, I23 in the event that the housewife has made a mistake in the setting of the adjustments 28, 28 and wishes to start over again.

Assuming now that it is desired to have the timer operate through an automatic cycle, say for starting a cooking operation which is to end at :30 o'clock and which is to be of three and one-half hours duration as mentioned above, the stop cooking adjustment 28 is set by the knob 28' at 5:30 o'clock on the clock dial ring 22, and the cooking hours adjustment 29 is set at the numeral 3 /2 on the scale 3|, both as indicated in Fig. 1. Thereupon, the control knob 33' is rotated in a counter-clockwise direction to bring the index pointer 33" into the set position 84.

The setting operation is now completed, and the timer is in readiness to go through its automatic cycle at the prescribed times. This setting operation can of course be performed in the morning, noon or any hour in the afternoon preceding the time when the cooking operation is to start. For example, the clock hands in Fig. 1 illustrate that the set condition has been established in the timer at or before 1:19 oclock. In this set condition of the parts, the multiple stop plate II9 will occupy the position illustrated in Fig. 4, with its first stop shoulder I22 abutting against the trip lever I01. In this position of the control member, the main switch cam has its lobe I2 I bearing against the insulating strip I28 for holding the switch contacts I3I, I3I in open circuit positions. The pilot switch cam I45 is now holding th pilot switch I46 closed, so that the pilot light 42 and the three lights 542 are illuminated for indicating that the timer is in its set position. As the time approaches for starting the cooking operation, the continuously driven roller IOI encounters the short cam 99, which has an angular setting predetermined by the position of the cooking hours adjustment 29. The roller rides down the slope of said cam, thereby thrusting the sleeve I03 downwardly and imparting a retractlve movement to the tripping lever I01. Substantially at the time when the roller reaches the peak of the cam 99, the tripping lever has been retractecl just enough to clear the first stop shoulder I22 of the stop plate II9. Instantly upon the tripping of this first stop shoulder, the control assembly rotates quickly through a one step advancement, bringing the second stop shoulder I23 up against the tripping lever I01, said second stop shoulder projecting outwardly to a greater radius than the first stop shoulder, as previously described. The one step advancement of the control member brings the flat stop I2I of the main switch cam into substantial parallelism with the insulating strip I28, permitting said strip and the movable contacts I 3 I, I3 I to flex inwardly into circuit closing position. This completes the circuit to the heating element I 58, the manually actuated switch I 55 having been previously set in its position. The pilot light cam I45 still maintains the pilot switch I46 in closed position, so that the pilot light 42 and the three lights 542 will remain illuminated for indicating that the heating element I56 is still under the control of the automatic timer. The continued time-driven motion of the roller IOI finally brings it into engagement with the relatively long cam 98 as the time approaches for stopping the cooking opera tlon. Substantially at the time that the roller IOI reaches the peak of the cam 88, the tripping lever I01 has been retracted sufficiently far to clear the second stop shoulder I25 of the stop plate H8. Hence, the control assembly is permitted to quickly rotate through a second step of advancing movement, this bringing the third stop shoulder I 24 up against the side of the tripping lever I01. This second step of advancing movement of the main switch cam I2I brings the cam lobe I2 I"' up against the insulating strip I28, flexing this strip outwardly and moving the contacts III, III to open circuit position. Thus, energization of the heating element I is interrupted at the time previously set for stopping the cooking operation. In this position of the parts, the pilot switch cam I45 is still holding the switch I45 closed for maintaining the pilot light 42 and the three lights 542 illuminated, these lights serving to indicate to the housewife that the circuit to the heating element I is still under the control of the automatic timer, in the sense that the automatic timer is retaining the switch contacts I3I, I3I in their open circuit position; and that a resetting operation must be performed for bringing the timer back to its normal condition with the switch contacts III, Ill closed. Thus, the housewife is apprised of the fact that she must depress the plunger rod 38 for shifting the sleeve I03 down through a final depressing movement, the range of which movement causes the tripping lever I01 to clear the third stop shoulder I24. The clearing of this last stop shoulder permits the control assembly to advance through a third and final step of rotation, thereby moving the cam lobe I2I"' away from the insulating strip I28 and permitting the switch contacts III, I8I' to move back to a normal, closed circuit position. Such third step of angular movement of the pilot switch cam I45 permitted the switch I46 to open, thereby extinguishing the pilot light 42 and the three lights 542, and indicating to the housewife that the timer is now restored to its normal position.

Referring now to the interval timer or time signal apparatus, this is driven from the gear teeth 58 in the upper end of the toothed drive shaft 61, the latter transmitting rotation to a gear wheel I1I which is Journaled on the underside of the left hand frame plate 48. Th gear wheel I1I meshes with the lower end oi. the relatively long idler pinion I12 which has its lower end journaled in a lug punched downwardly from the plate 49 and which has its upper end Journaled in a small upper plate I14. The main body of this upper plate I14 is spaced upwardly from the plate 49, and mounted between these two plates is a relatively large spur gear I11 which is driven from the pinion I12. As best shown in Fig. 3, the gear I11 is provided with a hub I18 which is capable of rotating freely on a vertical spindle I19. Fixedly secured to the lower end of said spindle is a bushing I8I which has a rotatable bearing support in the frame plate 45, the spindle also having a bearing support in the upper plate I 14. Fixedly secured to the upper end of the spindle is the knob 44 which serves to set the interval timer. Rigidly secured to the bushing I8I is a time settable arm I58, disposed below the spur gear I11. A spring-arm spider I84 has its central portion rigidly secured to the bushing I8I and arm I88, and has its spring-arms bearing with a resilient frictional contact against the bottom surface oi the spur gear I 11. The latter gear rotates continuously, and the gear ratio of the drive thereto is such that this gear makes one complete revolution each hour, the scale markings 44' on the knob 44 representing the sixty minutes of this hour. The spring-arm spider I84 functions as a friction slip e c h for transmitting rotating torque from this continuously rotating gear ill to the time settable arm I83 and spindle I19. The torque transmitted through this slippage clutch causes the arm I 88 to revolve in the direction indicated by the arrow in Fig. 4, until said arm encounters a, stationary stop shoulder I85, this preferably consisting of a lug punched upwardly from the body of the plate 49. It will be seen from the foregoing that when the knob 44 is given a counterclockwise adjusting rotation to establish a time setting of minutes, minutes or any other desired time with respect to the index marker 45 (Fig. 1), the settable arm I83 will be revolved a corresponding amount away from the stop lug I85. The knob and arm can be rotated in this direction, counter to the direction of rotation of the gear I11, by virtue of the slippage which is permitted to occur at the friction clutch I84. Immediately that the adjusting knob has been given this desired time adjustment, the knob and arm I83 start their return motion under the driving torque of the gear I11, the knob and arm continuing this return motion back to their normal position, defined by the arm engaging the stop lug I85.

The arm I83 has a pointed or wedge-shaped outer end which is adapted to cooperate with a corresponding wedge-shaped formation I81 on a tripper lever I88, this occurring just before the settable arm I83 arrives back in its normal position in engagement with the lug I85. The tripper lever is pivoted on a pin I89 extending upwardly from the frame plate 49, and the lever is yieldingly held in the normal position illustrated by a tension spring I! which has one end hooked to an apertured arm I92 extending from said lever, and which has its other end hooked to a lug I83 projecting up from the plate 49. The outwardly extendin arm of said lever carries a downwardly extending roller I94 composed of insulating material. This roller is adapted to actuate a snap switch I95, best shown in Figs. 8, 9 and 10. The switch is mounted on an insulating base I98, and comprises a stationary contact I91 and a movable contact I98 adapted to snap into and out of engagement with the stationary contact. The movable contact is in the form of a long strip of metal having its upper end secured by a rivet I99 to a biasing snap strip HI, and having an outwardly curved lower extremity which constitutes the contact surface adapted to engage with the stationary contact I91. The lower portion of the strip 2III has a laterally bent extremity which is attached by a connector rivet 282 to the insulating plate I96, and the upper end of said strip has a laterally curved end 20m against which the insulating roller I 94 is adapted to engage for actuating the switch. Referring to Figs. 10 and 11, that portion of the strip 2III disposed below the rivet I99 is provided with two parallel slots 20Ib which produce a central strip or ribbon portion 28Ic and the two lateral strips or ribbons 20Id-2IIId. These strips or ribbon portions are so treated and shaped that the middle strip or ribbon portion 2IIIc has a greater effective length than the side portions 20Id. For example, the median zone of the central ribbon, represented by the opposite lines of cross-hatching 28Ie, is given a tension stretch by a stamping or other shaping operation, whereby the metal is elongated so as to make the central ribbon portion 28Ic of greater length than the side ribbon portions 2 d. Furthermore, the effective length of the side ribbon portions may be shortened relatively to the central portion by forming a slight kink or bend in each side ribbon portion, this bend being located intermediate the upper and lower ends of the ribbon portions and being in a direction toward the strip I98 which constitutes the movable contact. Such bending shortens the effective length of the side ribbon portions relatively to the central ribbon portion. Referring to Fig. 11, the side portions are also given a forward slope or bend, to have their outer edges extend forwardly in a direction toward the movable contact strip I98. This adds stiffness to the side portions, so that the major portion of the snap flexure occurs in the central portion 2IIIc. In the operation of this snap switch, when the insulating roller I94 engages the bent upper end "Ia and starts flexing the switch structure toward the dotted line position shown in Fig. 8, the member 28I is flexed laterally a substantial distance before the differential stresses in the central portion 28Ic and in the side portions 20Id result in the over-center snap. Before the snap, the central portion occupies a position which curves or bows rearwardly (in a direction away from the movable contact strip I98) with respect to the side portions Mid, and these side portions extend or are disposed in a position forwardly of the central portion. As the assembly is flexed backwardly, the differential stress continues until the over center snap occurs, by which the central portion 20Ic is snapped or bowed forwardly toward the movable contact strip I98. The action causes a quick movement of the contact strip I98 into engagement with the stationary contact I91. Having snapped into such a closed position, the movable contact remains in engagement with the stationary contact during any further motion of the insulatin roller I94 in this same direction. In the retractive move.

; ment of the roller in the opposite direction, the

switch assembly flexes back toward its normal position, and at a certain point the over-center snap action occurs in the reverse direction for quickly separating the movable contact strip I98 from the stationary contact I91.

As shown in Fig. 2, this snap switch I controls the circuit of a signal buzzer 205. Referring to Fig. 8, the buzzer comprises a core 288 and a Winding 201 mounted thereon, this core and winding constituting the movable element of the buzzer. The core is composed of a magnetic metal, and formed in the lower end thereof is a guide bore 208 which has a sliding fit over a stud 289 projecting upwardly from the frame plate 48. The stud 209 is preferably composed of brass or other nonmagnetic metal. The frame plate 48 is composed of a magnetic metal so that when the core 286 is energized it tends to move downwardly toward the plate 48. A compression spring 2 interposed between the upper end of the stud 289 and the end of the bore 208 normally holds the core and winding in an elevated posit on, as shown. The upper end of the core 296 is formed with a guide pin 2I2 which has a slidable fit in a guide bore 2 I3 formed in an adjustable guide screw 2I4. Said screw threads through a tapped hole in the upper frame plate 41, and is adapted to be locked in any vertical position of adjustment by a lock nut 2I5. The screw 2 is preferably composed of brass or other nonmagnetic metal. The pressure of the spring 2 normally holds the shouldered upper end 2I5 oi the core against the lower end of the guide screw H4. The main body of the core 208 is disposed in closer proximity to the lower frame plate 48 than it is to the upper frame plate 41, and hence upon energization of the winding 201 the core and winding tend to move as a unit downwardly toward the plate 48. The lower end or the core striking this plate constitutes one end stop for the movable unit, and the shouldered upper end of the bore striking the guide screw 2 constitutes the other end stop for the movable unit. It will be understood that the winding 281 is energized by the alternating current which operates the synchronous electric motor 8|. Hence, the movable buzzer unit 206-481 tends to vibrate with the same frequency as the alternating current. The degree of loudness resulting from the movable unit striking the aforementioned end stops can be increased or decreased by screwing the adjusting screw 2 upwardly or downwardly, thereby adjusting the distance between the end stops.

When the housewife desires to set the interval timer for a certain time period, as for example to call her attention to a particular cooking operation upon the expiration of say 20 minutes, she will turn the adjustable knob 44 in a counterclockwise direction to place the "20 minute marking of the knob in registration with the index pointer 45. This revolves the arm I83 9. predetermined distance away from the stationary stop I85 in a counterclockwis direction. The continuously rotating gear I'll, revolving one revolution per hour, immediately starts to drive the arm I83 back toward the stop I85 in a clockwise direction of motion, such drive being transmitted through the friction clutch I84. Referring to Fig. 4, when the arm I83 arrives in proximity to the stop I85, th wedge-shaped outer end of said arm engages the wedge-shaped formation I81 on the lever I88, thereby rocking the lever I88 in a counterclockwise direction with the continuous motion of the arm I83. Such rocking movement of the lever I88 operates through the insulating roller I94 to close the snap switch I95, as described above. The snap switch is only held in its closed position tori-a brief time, say from 10 to 30 seconds or so, because of the small area of contact between the wedge-shaped end of the arm I83 and the wedge-shaped formation I81 on the lever I88, and also because of the adjusted position of the snap switch I95 relatively to the path of travel of the roller I84. During this closed condition of the snap switch, the buzzer device 205 sounds its signal by a continuous vibration. When the wedge-shaped outer end of the arm I83 slips past the wedge-shaped portion I81 of the lever I88, the lever I88 is immediately restored to normal position, and the arm I83 is thereafter brought to a stop against the shoulder I85.

While I have illustrated and described what I regard to be the preferred embodiment of my invention, nevertheless it will be understood that such is merely exemplary, and that numerous modifications and rearrangements may be mad therein without departing from the essence of the invention. In this regard, I wish to point out that my improved timer mechanism is not necessarily limited to the control of an electric switch, but may be employed for other purposes, such as for effecting the automatic time control of a gas valve governing the operation of a burner in a gas range. as fully disclosed in Patent No. 2,302,624 to William P. Gallagher for Bumer control apparatus."

What is claimed is as follows:

1. In timing apparatus for governing the timed operation of a control device, a clock mechanism, a time scale, a first adjustable sheet member c0- operating with the clock mechanism and the time scale and movable to various locations for predetermining the time when the clock mechanism moves said control device to one position, a sec ond adjustable sheet member overlying said first member also cooperating with the clock mechanism and the time scale and movable to various locations for predeterminin the time when the clock mechanism moves said control device to a second position, means providing a background beneath at least a portion of said first and second members, said first member being apertured, said second member also being apertured, the apertures in said members being located to register in certain relative locations, said apertures extending from the points indicating their respective predetermined times relative to the time scale toward each other so that the registering portions of the apertures will reveal said background between said points.

2. Timing apparatus including a control device movable to a plurality of positions, a timing drive mechanism, a time scale, a first adjustable member movable to various locations and having a sheet portion and an index cooperating with said time scale, a second adjustable member movable to various locations and having a sheet portion and an index cooperating with said time scale, means cooperating with said drive mechanism and said adjustable means for operating said control device from one position to another according to the locations of the adjustable members with respect to said time scale, means providing a background beneath a portion of said sheet portions, each of said sheet portions being apertured with the apertures aligned and extending from the indices cooperating with the time scale toward each other to form registering zones revealing the background between said points.

3. Timing apparatus including a control device movable to a plurality of positions, a timing drive mechanism, a time scale, a first adjustable member movable to various locations and having a sheet portion and an index cooperating with said t me scale, a second adjustable member movable to various locations and having a sheet portion and an index cooperating with said time scale, means cooperating with said drive mechanism and said adjustable means for operating said control device from one position to another according to the locations of the adjustable members with respect; to said time scale, means providing a background beneath a portion of said sheet portions. each of said sheet portions being apertured with the apertures aligned and extending from the indices cooperating with the time scale toward each other to form registering zones revealing the background between said points, one of said adjustable members being provided with a time graduated scale for measuring the revealed background.

4. Timing apparatus including a clock comprising a clock dial having dial numerals and hour and minute hands cooperating with the dial and mechanism for driving the hands, first and second adjustable members concentric and rotatable with respect to said dial and having sheet portions flanking and provided with indices cooperating with said dial to locate the members with respect to the dial, said sheet portions being provided with window means in alignment on the same radius extending toward each other from said indices, means Providing a background beneath the path of said window means and revealed by the registered zones of the window means, a control device movable to a plurality of positions, means cooperating with said clock mechanism and said adjustable members for moving said control device from a first position to second position when the clock reaches the time indicated by one of the indexes and for moving the control device from said second position to another position when the clock reaches the time indicated by another index.

5. Timing apparatus including a clock comprising a clock dial having dial numerals and hour and minute hands cooperating with the dial and mechanism for driving the hands, first and second adjustable members concentric and rotatable with respect to said dial and having sheet portions flanking and provided with indices cooperating with said dial to locate the members with respect to the dial, said sheet portions being provided with window means in alignment on the same radius extending toward each other from said indices, means providing a background beneath the path of said window means and revealed by the registered zones of the window means, a control device movable to a plurality of positions, means cooperating with said clock mechanism and said adjustable members for moving said control device from a first position to a second position when the clock reaches the time indicated by one of the indexes and for moving the control device from said second position to another position when the clock reaches the time indicated by another index, and a time graduated scale carried by one of said adjustable members to measure the registered zone of the window means to disclose the length of the time period between the members.

6. Timing apparatus including a clock comprising a clock dial having dial numerals and hour and minute hands cooperating with the dial and mechanism for driving the hands, first and second adjustable members concentric and rotatable with respect to said dial and having sheet portions flanking and provided with indices cooperating with said dial to locate the members with respect to the dial, said sheet portions being provided with window means in alignment on the same radius extending toward each other from said indices, means providing a background beneath the path of said window means and revealed by theregistered zones or the window means, a control device movable to a plurality of positions, means cooperating with said clock mechanism and said adjustable members for moving said control device from a first position to a second position when the clock reaches the time indicated by one of the indexes and for moving the control device from said second position to another position when the clock reaches the time indicated by another index, said sheet portions being in the form of sheet metal discs.

7. Timing apparatus including a clock comprising a clock dial having dial numerals and hour and minute hands cooperating with the dial and mechanism for driving the hands, a control device movable to a plurality 01 positions, a settable means cooperating with said clock mechanism for controlling the operation of said control device in accordance with a pre-selected time setting, an illuminated indicating means for indicating in cooperation with said clock dial the beginning, duration and end of the pre-selected time settin and means for illuminating said indicating means when said settable means is set to operate the control device and for preventing illumination of the indicating means when the settable means is set not to operate the control device.

8. Timing apparatus including a control device movable to a plurality of positions, a timin drive mechanism, a settable means cooperating with said drive mechanism for controlling the operation of said control device in accordance with said timing drive mechanism, an illuminated indicating means for indicating the beginning, duration and end of the operation of the control device, and means for illuminating said indicating means when the settable means is set to operate the control device and for preventing illumination of said indicating means when the settable means is set not to operate the control device.

9. Timing apparatus including a clock comprising a clock dial having dial numerals and hour and minute hands cooperating with the dial and mechanism for driving the hands, a control device movable to a plurality of positions, a settable means cooperating with said clock mechanism for controlling the operation of said control device in accordance with a pre-selected time setting, an illuminated indicating means for indicating in cooperation with said clock dial the beginning, duration and end of the pre-selected time setting, said illuminated indicating means having means for uncovering a distinctively defined area bordering the dial numerals corresponding to the beginning, duration and end of the pre-selected time setting, and means for illuminating said indicating means when said settable means is set to operate the control device and for preventing illumination of the indicating means when the settable means is set not to operate the control device.

10; Timing apparatus including a clock comprising a clock dial having dial numerals arranged in a circle and an hour hand cooperating with the dial and mechanism for driving the hand, a control device movable to a plurality of positions, a settable means cooperating with said clock mechanism for controlling the operation of said control device in accordance with the beginning and ending of a pre-selected time setting, n

- plurality of rotatable adjustable members located concentrically with respect to said circle of dial numerals and rotatable to various locations with respect to the dial numerals, said rotatable members having means for uncovering a distinct defined area bordering the dial numeral circle extending from the portion of the dial numeral circle corresponding to the beginning of the pre-selected time .period to the portion of said circle corresponding to the end of said period for indicating in a comprehensive manner the beginning, duration and ending 0! the pre-selected time setting, and means for illuminating said defined area in such a way as to visibly-outline said area when said settable means is set to operate the control device and for preventing illumination of said area when the settable means is set not to operate the control device.

ROBERT R. CANDOR. 

